Targeting aurora kinase with MK-0457 inhibits ovarian cancer growth.

PURPOSE: The Aurora kinase family plays pivotal roles in mitotic integrity and cell cycle. We sought to determine the effects of inhibiting Aurora kinase on ovarian cancer growth in an orthotopic mouse model using a small molecule pan-Aurora kinase inhibitor, MK-0457. EXPERIMENTAL DESIGN: We examined cell cycle regulatory effects and ascertained the therapeutic efficacy of Aurora kinase inhibition both alone and combined with docetaxel using both in vitro and in vivo ovarian cancer models. RESULTS: In vitro cytotoxicity assays with HeyA8 and SKOV3ip1 cells revealed >10-fold greater docetaxel cytotoxicity in combination with MK-0457. After in vivo dose kinetics were determined using phospho-histone H3 status, therapy experiments with the chemosensitive HeyA8 and SKOV3ip1 as well as the chemoresistant HeyA8-MDR and A2780-CP20 models showed that Aurora kinase inhibition alone significantly reduced tumor burden compared with controls (P values<0.01). Combination treatment with docetaxel resulted in significantly improved reduction in tumor growth beyond that afforded by docetaxel alone (P

Overexpression of the centrosomal protein Aurora-A kinase is associated with poor prognosis in epithelial ovarian cancer patients.

PURPOSE: To assess the clinical significance of Aurora-A kinase, a centrosome-regulating serine-threonine kinase, in ovarian carcinoma. EXPERIMENTAL DESIGN: Aurora-A kinase expression was assessed by Western blot (cell lines) or immunohistochemistry (high-grade epithelial ovarian cancers), and clinical variables were collected by retrospective chart review. Centrosome amplification was assessed by immunofluorescence in cell lines, and by immunohistochemistry in patient samples. RESULTS: All ovarian cancer cell lines exhibited significant Aurora-A kinase protein overexpression, and all except A2780-par had centrosome amplification, a characteristic of mitotic dysregulation leading to genomic instability. Fifty-eight of 70 patient samples (82.8%) exhibited Aurora-A kinase overexpression compared with normal ovarian surface epithelium. High Aurora-A kinase expression was strongly associated with supernumerary centrosome count in tumor cells (P<0.001). Tumors with the greatest Aurora-A overexpression (n=24) had decreased patient survival (median survival, 1.44 versus 2.81 years; P=0.01). High Aurora-A expression and suboptimal surgical cytoreduction remained predictors of poor survival (P<0.05) by multivariate analysis. CONCLUSIONS: Aurora-A kinase is overexpressed by a substantial proportion of ovarian cancers and is associated with centrosome amplification and poor survival. It may be a useful prognostic marker and target in ovarian cancer.